Worker: Make WorkerMicrotaskRunner a private inner class of WorkerThread
This CL makes WorkerMicrotaskRunner a private inner class of WorkerThread
because the task runner is basically used only from WorkerThread and it
needs to access a function of WorkerThread that is currently public but should
be private.
This also renames performShutdownTask() to performShutdown() for improving
naming consistency with prepareForShutdown().
This should not change any behavior.
BUG=487050, 575532
Review-Url: https://codereview.chromium.org/2006273003
Cr-Commit-Position: refs/heads/master@{#395817}
2 files changed
